Derivative Help

find the derivative:
s(x)=sin^2⁡((3x-pi))

could someone show me how to find the derivative of this using both methods of the chain rule: F'(x) = f '(g(x)) g '(x) and (dy/du)*(du/dx).I keep getting 2(sin(3x-pi)(-3cos(3x)) which i know to be incorrect

could someone show me how to find the derivative of this using both methods of the chain rule: F'(x) = f '(g(x)) g '(x) and (dy/du)*(du/dx).I keep getting 2(sin(3x-pi)(-3cos(3x)) which i know to be incorrect